Road vehicles that have powertrains require lubricating fluids to continuously operate. More specifically, the engine and especially, the automatic transmission, require lubricating fluids or oils to maintain their operation and extend their useful life. Additionally, these fluids are passed through filters to remove contaminants and metal shavings caused by normal operation of the powertrain. The lubricating fluids and filters need to be replaced on regular intervals during the life of the vehicle. Generally, the change interval for replacing the engine lubricating fluid and filter is different from the change interval for replacing the transmission lubricating fluid and filter. Often the vehicle owner or operator is unaware of when these lubricating fluids and filters require replacement. As a result, many times the fluids and filters go without replacement. Alternatively, the fluids and filters are replaced unnecessarily. If a filter is not changed at its required interval, damage can occur especially in the transmission. A plugged or clogged transmission filter can increase the pressure in the main case of the transmission causing damage.
Thus, there is a need for a method for determining the status of the fluid filters, especially, the transmission filter. The method should alert the vehicle operator or owner that the fluid filter needs to be replaced. Moreover, the method should also check for hardware faults in the fluid filter monitoring system.